Faulkner J A, Zerba E, Brooks S V
Department of Physiology, University of Michigan, Ann Arbor 48109-0622.
Am J Physiol. 1990 Aug;259(2 Pt 2):R259-65. doi: 10.1152/ajpregu.1990.259.2.R259.
Our purpose was to study the effect of a decrease in skeletal muscle temperature on single and repeated shortening, isometric, and lengthening contractions of mammalian skeletal muscles. Fast extensor digitorum longus muscles of mice were studied in situ and in vitro at 25 and 35 degrees C. No difference in isometric force was observed, but maximum and sustained powers were reduced by 40 and 62%, respectively. With cooling, maximum power absorption, which is proportional to the external work required to lengthen the muscle, increased significantly at each velocity of lengthening from 0.5 to 4.0 optimum fiber length/s. The 10 degrees C decrease in muscle temperature produced a decrease in power that was primarily a result of the decrease in the velocity of shortening, whereas the increase in power absorption was likely due to an increase in the number of strongly bound cross bridges resulting from a decreased rate of detachment. During voluntary exercise at decreased muscle temperatures, maximum and endurance performances are inevitably impaired by the decreases in maximum and sustained power of individual motor units.
我们的目的是研究骨骼肌温度降低对哺乳动物骨骼肌单次和重复缩短、等长及拉长收缩的影响。在25摄氏度和35摄氏度下，对小鼠的快速趾长伸肌进行了原位和体外研究。未观察到等长力的差异，但最大功率和持续功率分别降低了40%和62%。随着温度降低，最大功率吸收（与拉长肌肉所需的外部功成正比）在从0.5到4.0最佳纤维长度/秒的每个拉长速度下均显著增加。肌肉温度降低10摄氏度导致功率下降，这主要是由于缩短速度降低所致，而功率吸收增加可能是由于解离速率降低导致强结合横桥数量增加所致。在肌肉温度降低时进行自愿运动期间，最大和耐力表现不可避免地会因单个运动单位的最大功率和持续功率降低而受损。
